later . . .
Matter solved: added root folders to library.
I can now generate a print from all folders using the library.
Have to confess, did not think of this before as I have never been using the library sofar.
For me the matter is solved.
To everybody: thank you all for thinking along with me!
@krksoft : maybe the issue I submitted in my earlier post, might help to further improve your program?
(if -of course- it is something that cannot be yet solved by the program already)